Materials : Metals and Non – Metals

Notes of chapter: Materials : Metals and Non – Metals are presented below. Indepth notes along with worksheets and NCERT Solutions for Class 8.

(1)Metals-

The materials which are hard, lustrous, malleable, ductile, sonorous and good conductors of heat and electricity are called metals.

Eg:- Iron, copper, aluminium, calcium and magnesium etc.

(2)Non – Metals-

The materials which are soft, dull in appearance, break down into powder on tapping with force, not sonorous and are poor conductors of heat and electricity are called non – metals.

Eg:- Sulphur, carbon, oxygen, phosphorus etc.

(3) Physical properties of metal and non – metal-

Properties	Metal	Non – Metal
Malleability	can be beaten into thin sheets	can not be beaten into thin sheets
Conductivity	Heat and electricity can travel, ie, we feel heat after touching hot steel pan or feel electric shock after touching electric wire .	Heat and electricity can not travel,ie, we do not feel heat after touching hot wooden spoon or feel electric shock after touching electric wire with rubber or plastic handle of screw driver.
Ductility	can be drawn in to wires	can not be drawn in to wires
Sonorous	can produce ringing sound	can not produce ringing sound
Lustrous	shines	does not shine
Hard	They are hard in nature.	They are soft in nature.
Example	Iron, copper, aluminium, calcium and magnesium etc.	Sulphur, carbon, oxygen, phosphorus etc.
Exceptions	Sodium and potassium are soft and can be cut by a knife. Mercury is the only metal which is found in liquid state at room temperature.

(4) Chemical properties of metals and non – metals-

Properties	Metal	Non – Metal
Reaction with oxygen	Metal + moist air →Metallic oxides Metallic oxides + red litmus paper → red litmus paper turns blue. Metallic oxides are basic in nature.	Non – metal + H₂o→ non – metallic oxides Non -Metallic oxides + blue litmus paper→ blue litmus paper turned red. Metallic oxides are acidic in nature.
Reaction with water	produce metal hydroxides and hydrogen gas. Sodium metal is very reactive with water and oxygen and a lot of heat is generated in the reaction. Hence, Sodium is stored in the kerosene.	do not react with water. But react with air. Hence, they are stored in the water. Eg:- phosphorus is kept in the water to prevent the reaction with atmospheric oxygen.
Reactions with acids	produce metal salts and hydrogen gas.	do not react
Reactions with bases	reacts with sodium hydroxide to produce hydrogen gas.	reactions with base are very complex.
Displacement reactions	more reactive metal displace less reactive metals from their aqueous solution Eg:- Zn replaces Cu from copper sulphate (CuSo₄)